The environment is changing so that there is less and less space for people to exercise in. The society is also changing so that there is less and less time left for people to exercise. Therefore, people exercise less and less, and this jeopardizes physical and mental health. According to reports, light and frequent exercise improves human health as well as more intense but less frequent exercise. To facilitate exercise, there have been various exercise machines. With these exercise machines, people can exercise whenever they are available.
A typical exercise bike or oval-movement exercise machine includes two cranks, an active wheel and a load wheel. The cranks are connected to the active wheel. The active wheel is connected to the load wheel via an ordinary belt, a timing belt or chain. The load wheel exerts a load on the active wheel through the belt while a user is working out. The load wheel may include external or internal magnets or frictional elements. The active wheel and the load wheel are provided on two different axles, and this renders the exercise bike or oval-movement exercise machine bulky. The bulkiness intimidates customers who intend to use exercise machines at their not-big-enough apartments.
There have been attempts to reduce the distance between axles that support an active wheel and a load wheel and the dimensions of parts of an exercise machine. However, these attempts have not been proved to be successful.
Should the cranks be directly connected to the load wheel, i.e., without any active wheel, the rotational speed of the load wheel is the rotational speed at which a user treads the cranks. The rotational speed of the load wheel would be too low, i.e., the rotational momentum of the load wheel would be too small to ensure smooth rotation of the load wheel, particularly near upper and lower dead points.
The present invention is therefore intended to obviate or at least alleviate the problems encountered in prior art.